Secretary of State John Hay sent his Open Door Notes (1899-1900) to world powers to protect United States trading interests in China. The correct option among all the options that are given in the question is option "3". These notes were mainly in regards to providing equal opportunity for trades in China and also respecting China's sovereignty, territorial integrity and administration. The principles of operating in China was the same for the British as well as for the United States, but John Hay was the first person to give it a written form. After this the official policy of the United States was based on the written document during the first half of the 20th century.
Answer:
Head loss in turbulent flow is varying as square of velocity.
Explanation:
As we know that head loss in turbulent flow given as

Where
F is the friction factor.
L is the length of pipe
V is the flow velocity
D is the diameter of pipe.
So from above equation we can say that

It means that head loss in turbulent flow is varying as square of velocity.
We know that loss in flow are of two types
1.Major loss :Due to surface property of pipe
2.Minor loss :Due to change in momentum of fluid.
The concentration of the hydroxide ions after 50 ml of 0.250M NaOH is added to 120ml of 0.200M Na2SO4 is 7.35 x 10^-2 M.
What is meant by concentration?
Concentration is the total amount of solute present in the given volume of solution. this is expressed in terms of molarity, molality, mole fraction, normality etc. The term concentration mostly refers to the solvents and solutes present in the solution.
Concentration of hydroxide ions can be calculated by,
M (OH^-) = V (NaOH) x M (NaOH) / V (total) = 50ml x 0.250M / 50ml + 120ml = 0.0735M = 7.35 x 10^-2 M.
where M (OH^-) = concentration of hydroxide ions, V(NaOH) = volume of NaOH, M(NaOH) = concentration of NaOH.
Therefore, the concentration of the hydroxide ions after 50 ml of 0.250M NaOH is added to 120ml of 0.200M Na2SO4 is 7.35 x 10^-2 M.
To learn more about concentration click on the given link brainly.com/question/17206790
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Answer: Pseudopodia are temporary and cytoplasm-filled parts of the cell membrane that are able to change their form in order to move. They are used in some eukaryotic cells to move around or to eat. Most cells that do this are called amoeboids.